Derating For Running At Low Speeds - Danfoss VLT Micro Drive FC 51 Operating Instructions Manual

7. Specifications
For altitudes above 2000 m, please contact Danfoss Drives regarding PELV.
Below 1000 m altitude no de-rating is necessary but above 1000 m the ambient temperature or
the maximum output current should be decreased.
Decrease the output by 1% per 100 m altitude above 1000 m or reduce the max. ambient tem-
perature by 1 degree per 200 m

7.3.4. Derating for Running at Low Speeds

When a motor is connected to at frequency converter, it is necessary to check that the cooling of
the motor is adequate.
A problem may occur at low speeds in constant torque applications. Running continuously at low
speeds – below half the nominal motor speed – may require additional air cooling. Alternatively,
choose a larger motor (one size up).
7
34
VLT Micro Drive FC 51 Operating Instructions
MG.02.A2.02 - VLT ® is a registered Danfoss trademark